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Unlock with Pro - from £29/user/moDetect WordPress Core Interpretation Conflict Vulnerability (CVE-2026-63030) in Microsoft Sentinel
WordPress Core contains an interpretation conflict vulnerability (CWE-436) fixed in WordPress 7.0.2, in which differing parsing/interpretation behavior between components of the request-handling pipeline (e.g., PHP, web server, and WordPress core routing/sanitization layers) allows an attacker to smuggle or disguise malicious input so it is treated differently downstream than upstream validation expected. This class of flaw is commonly abused to bypass input filtering, achieve request smuggling-style effects against reverse proxies/CDNs fronting WordPress, or slip malicious payloads (e.g., leading to file write, privilege escalation, or authentication bypass) past security controls that assume a single canonical interpretation of the request. The vulnerability is listed in CISA KEV, indicating confirmed active exploitation in the wild, and is subject to CISA BOD 26-04 remediation timelines for federal and high-risk entities. No CVSS score has been published at time of writing; PoC details are not publicly available, but active exploitation implies working exploit code exists among threat actors. Detection focuses on anomalous WordPress core request patterns consistent with interpretation-conflict abuse: malformed/duplicate headers, ambiguous content-length/transfer-encoding combinations, unusual URL encoding or path traversal-like sequences hitting wp-admin/wp-login/wp-json endpoints, and post-exploitation indicators such as new admin users, unexpected plugin/theme file writes, or webshell drops shortly after anomalous requests.
MITRE ATT&CK
KQL Detection Query
let SuspiciousPaths = dynamic(["/wp-admin/", "/wp-login.php", "/wp-json/", "/xmlrpc.php"]);
AppServiceHTTPLogs
| where TimeGenerated > ago(24h)
| where CsUriStem has_any (SuspiciousPaths)
| where (CsUriQuery has "%00" or CsUriQuery has "%0d%0a" or CsUriQuery has ".." or CsUriStem matches regex @"%[0-9a-fA-F]{2}%[0-9a-fA-F]{2}")
| extend AnomalousHeader = iff(CsBytes == 0 and Method == "POST", true, false)
| where AnomalousHeader == true or ScStatus in (200, 201, 302)
| summarize RequestCount = count(), Paths = make_set(CsUriStem), Queries = make_set(CsUriQuery) by CIp, bin(TimeGenerated, 5m)
| where RequestCount > 5
| project TimeGenerated, CIp, RequestCount, Paths, Queries Detects anomalous WordPress core requests consistent with interpretation-conflict exploitation attempts: encoded/ambiguous payloads hitting sensitive wp-admin, wp-login, wp-json, and xmlrpc endpoints combined with bursty request patterns.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate REST API automation or mobile app clients hitting wp-json in bursts
- Security scanners/vulnerability assessment tools generating encoded payloads against wp-admin
- CDN or load balancer health checks and cache-busting query strings resembling encoded sequences
Other platforms for CVE-2026-63030
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Simulate encoded null-byte request to wp-login.php
Expected signal: Web server access log entry for /wp-login.php with query string containing %00 and the source IP of the test host.
- Test 2Simulate ambiguous Transfer-Encoding/Content-Length header request
Expected signal: Web server or WAF log entry showing conflicting Transfer-Encoding and Content-Length headers on a request to /xmlrpc.php.
- Test 3Simulate burst of encoded traversal requests to wp-json
Expected signal: Eight access log entries within a short window from the same source IP hitting /wp-json/ with encoded traversal sequences in the URI.
References (5)
- https://wordpress.org/news/2026/07/wordpress-7-0-2-release/
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
- https://nvd.nist.gov/vuln/detail/CVE-2026-63030
- https://isc.sans.edu/diary/rss/33168
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